Improvement in keys for use with electrical apparatus



J. GLMSTED.

Keys for use with Eiectrical Apparatus.

N0. 333,797, Patented Deca10,i872.

.MlFHUTO-L/THOGHAPH/C CO H UUSEUENEIS PROCESS) UNITED STATES PATENTQFFIGE.

JOSEPH OLMSTED, OF PROVIDENCE, RHODE ISLAND.

Specification forming part of Letters Patent No. 133,797, dated December10, 1872.

To all whom it may concern:

Be it known that I, JosEPH OLMSTED, of the city and county ofProvidence, in the State of Rhode Island, have made certain new anduseful Improvements in Key-Boards for Graduating the Power ofElectro-Magnets; and I do hereby declare that the followingspecification, taken in connection with the drawing making a part of thesame, is a full, clear, and exact description thereof.

Figure 1 is an isometrical view of my device. Fig. 2 is a sectionthereof. Fig. 3 is a top view.

The object of my invention is twofold: first, to graduate the electriccurrent in such a manner as will place the amount of power used underthe immediate control of the operator; second, to reverse the currentfor the purpose of demagnetizing the magnet and destroying the permanentmagnetism, thus bringingthe parts magnetized to their former neutralcondition.

My invention is adapted to different mechanisms operated by an electriccurrent, although it is more especially designed for the operation ofwhat is generally known as the electric car-brake.

I shall, therefore, for the sake of convenience and clearness, describeit in connection therewith.

In order to make the use of electricity practical in applying acar-brake, as well as for various other purposes, it first becomesimportant to graduate the current, for the reason that more power isrequired at some times than at others, it being well understood that theamount of power necessary is in proportion to the distance within whicha train must be stopped, and that to use more power than is actuallyrequired is to produce unnecessary wear and strain.

In my invention the current may be divided into three parts, andone-third, two-thirds, or the whole used, as the distance or thenecessities of the case may require.

In the drawing, Figures 1, 2, and 3, A is a small bed or table, havingupon its under side a coil of resistance-wire, B. O and (3 are wiresconnecting with the battery, and D and D wires connecting with thebrakes. The wires 0 and O are connected with the conducting-pieces E E Eand F F F F the wires D and D with the conducting-pieces H and H, thecircuit being completed by the movable key I and the insulated spring K,the former connecting E E E with H, and the latter F F F F F with H. Themovable end of the key I, when the current is broken, rests between Eand F.

Commencing with the key I in this position, when the time arrives forapplying the brakes the engineer moves it from right to left until itrests between E andF as shown in Fig. 1. The circuit is now complete.The current flowing from the battery through the wire 0, as shown inFig. 1, is carried through the con ducting-piece E the key I,conducting-piece H, and the wire D to the brakes, and returning throughthe wire D, conducting-piece H, spring K, conducting-piece F to theresistance wire B, from the resistance-wire B to the wire L, and fromthe wire L through the conducting-pieee E to the wire (J, and back tothe battery. The current thus flowing through the whole of theresistance-wire B develops its least power.

As soon, however, as it becomes necessary to set up the brakes withgreater force, the engineer moves the key until it rests between E and FThe current now flows in the same manner, as before described, until,upon its return, it reaches the spring K, when it is conducted throughthe piece F and a small wire, M, to the middle of the resistance-wire,

B, from whence it passes back to the battery the same as before, and, asthe current only flows through one-half of the resistance-wire, agreater amount of power is brought into use than in the first instance.

If, upon nearing a station, or otherwise, a sudden stop is necessary,the engineer slides the key in the same direction until it rests betweenE and F The current now flows in the same manner, as at first described,until, upon its return, as before mentioned, it reaches the spring K,when it passes directly through the conducting-piece F to the wire L,and thence to the battery, without passing through any of theresistance-wire, thus carrying to the brakes a full undiminishedcurrent.

The train now being stationary, it becomes necessary to throw on thebrakes. As the armature oomes directly in contact the more breaking ofthe current would be insufficient to throw off the brakes, inasmuch asthe permanent magnetism would cause them to cling This difiicultyl forsome considerable time. easily overcome by moving the key hackto itsoriginal position, which brings itfor an instant of time between theconducting-pieces E and F thus producing a current in the oppositedirection, which neutralizes the permanent magnetism, the currentflowingthrough the wire 0, conducting-piece E wire N, conducting-piece Fspring K, conducting-piece H to the wire D, and returning upon the wireD through the conducting-piece H, key I, conducting-piece E to the wire0, thence to the battery.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The graduating-key I, in combination with the resistance-coil B, forthe purpose of regulating the resistance, in the manner sub- 1stantially as described.

2. The current-reverser operated by the key I, in the mannersubstantially as described.

3. A rheostat thrown in or out of the circuit by means of the key I, inthe manner substantially as described.

I JOSEPH OLMSTED,

Witnesses WALTER B. VINCENT, NATHANIEL L. MORGAN.

